Pulmonary hypertension, from prolonged pulmonary disease, developing dilatation of the right ventricle and finally progressing to right sided heart failure. Simultaneous mesurement of venous pressure (VP) and cardiac output (CO) with a method which was originally proposed by Hirakawa, was carried out, with some modification, to investigate the progress of the chronic pulmonary disease (CPD) to cor pulmonale. The change of the cardiac index (ΔCI) and that of the venous pressure (ΔVP) with exercise, i.e. "cardio-venous response" were studied in the patients of CPD and of cardiac disease without pulmonary disease. Pulmonary function study and blood gas analysis were performed on these patients to discover its relationship to the cardiac function, as estimated from "cardio-venous response" to exercise. Methods: The subjects were 51 patients of CPD, and 13 patients of cardiac disease. Patients were left quietly on the bed in the supine position for 1 hour. After the blood volume determination, to record the CO, the radiocardiograph (RCG) detector was plased on the anterior chest at the 4th intercostal spase, left sternal border. VP was obtained with a saline manometer, by modified Moritz-Tabora's method, in the cubital vein. With reference to RCG, radio-isotope serum albumin, ¹³¹I(RISA), 20 μCi, was injected intravenously and flushed immediately with 10 ml of 5% glucose to get complete and instantaneous injection into the cubital vein on the other side of the arm when the VP became stable. The distribution equilibrium count was recorded at the end of 7 minutes after the shot, keeping the detector at the same place. CO was calculated as follows. CO = (E/A) X blood volume where E: the equilibrium count rate (mm). A: the integrated area under the time-activity curve. Heart rate was monitored by electrocardiogram during examination. Flexion- extension exercise of the lower extremities was then started and continued for 4 minutes at a rate of 36 times a minute, avoiding straining as much as possible. -During that time, CO and VP were measured when the VP reached a relatively stable state. Parameters, including arterial blood gass analysis-pH, P_CO2, P_O2, O₂ Saturation, % vital capacity, and forced expiratory volume in 1 secound (FEV_{1.0 sec.}), were determined on the same day of studies on circulatory dynamics or on the next day, both at rest and during exercise, in the situation.

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In right bundle branch block (RBBB), there have been many reports studied experimentally and clinically as to the relationship between abnormal ventricular activation and changes in electrocardiographic QRS patterns. However, the number of lead points in conventional electro-and vectorcardiogram is not sufficient to record all the potential changes produced on the body surface in RBBB. To compensate for this limitation, the body surface isopotential map (hereafter abbreviated as map) has recently been introduced. This map is expressed in the form of an equipotential contour map based on the data from a large number of unipolar lead electrocardiograms on the body surface. Comparison with the conventional electro-and vectorcardiogram has shown that the map contains much information about local activation in the heart. Therefore, the map will be a more useful method in explaining several cardiac abnormal excitations. In this report, using a simulation of the ventricular propagation process and a method for computational reconstruction of the map which were developed by the author, simulation of the ventricular propagation in RBBB was performed and the map was reconstructed. The correlation between the reconstructed map and the propagation process in the heart model was used to investigate the genesis of a clinical RBBB map. Methods: 1. Simulation of the ventricular propagation process in RBBB As reported previously, the heart model based on the post-mortem human heart was stored in memory of a large digital computer. In order to simulate more precisely the propagation process than that in the previous heart model which was composed of a cluster of 3 mm cubic blocks, the block size was cut to the 1.5 mm cubic one. In this new heart model, simulation of ventricular propagation process in RBBB was performed.

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